Automatic pump control



April 18,1967 w. H. PEARCE 3,314,363

AUTOMATIC PUMP CONTROL Filed April 27, 1965 2 Sheets-Sheet 1 5/ W Z 28 7 24/ 4 20 6 v z 2 I A? V C /H /9 1033 g 32 22 l "22 /6 24 30 /6 f :EL :tZ: :7 /0 f is f? BY 1 f ATTORNEY April 18, 1967 w. H. PEARCE AUTOMATIC PUMP CONTROL 2 Sheefs-Sheet 2 Filed April 27, 1965 1N VENTOR WH/ E A IPCE ATTORNEY V///////////////////////// fi//// United States Patent i This invention relates to a novel automatic control for a pumping unit, and more particularly to a novel electric switch for automatically controlling the electric circuit of an electric motor pump in response to the liquid level in a receptacle to which the pump is connected.

The primary object of the invention is to rovide an automatic switch which may be located remote from a pump which is associated with and controls the liquid level of a receptacle, and which switch is connected by a pressure responsive means to said receptacle whereby variations in pressure caused by changes in the liquid level in the receptacle is transmitted to a part of the switch which is responsive to said such pressure variations to effect an opening or a closing of the switch in response to predetermined variations in the pressure imposed on said pressure responsive part of the switch.

Still another object of the invention is to provide a switch capable of opening and closing very rap-idly in response to predetermined changes in the pressure exerted on the pressure responsive part of the switch.

Various other objects and advantages of the invention will hereinafter become more fully apparent from the following description of the drawings, illustrating a presently preferred embodiment thereof, and wherein:

FIGURE 1 is a substantially central vertical sectional view of the automatic pump control or switch, taken substantially along a plane as indicated by the line 1-1 of FIGURE FIGURE 2 is a fragmentary vertical sectional view, on a substantially reduced scale relative to FIGURE 1, showing a container and associated parts, the liquid level Within which is controlled by the automatic pump control or switch;

FIGURE 3 is a fragmentary vertical sectional view taken substantially along the same plane as FIGURE 1, and illustrating one closed position of the switch;

FIGURE 4 is a fragmentary vertical sectional view, taken substantially on the same plane as FIGURE 1, showing a second closed position of the switch, and

FIGURE 5 is a cross sectional view through the switch taken substantially along the plane as indicated by the line 55 of FIGURE 1.

Referring more specifically to the drawings, the automatic pump control or switch in its entirety and comprising the invention is designated generally 7 and includes a switch body 8 formed of an electrical insulating material. The body 8 preferably comprises a block of a plastic material having a heighth greater than the width thereof, as seen in FIGURE 1. and substantially greater than its thickness, as seen in FIGURE 5.

The lower :lefthand corner of the block 8, as seen in FIGURE 1, is recessed to provide a reservoir 9 of substantial size, as seen in FIGURE-S 1 and 5, which is provided with a partition 10 which extends downwardly from the top thereof to adjacent its bottom and which divides said reservoir into a large outer chamber 11 and a small inner chamber 12. A passage 13 extends upwardly from the top of the outer chamber 11 through the upper end 14 of the block 8.

A horizontal passage 15 is formed in the block 8 and extends from the upper part of the reservoir chamber 12 partially across the width of the block 8 and, as seen in FIGURE 5, is provided with two enlarged portions 16 and 17. A passage 18 is formed in the block 8 and 3,314,363 Patented Apr. 18, 196 7 extends upwardly from the passage 15 between its enlargements 16 and 17 and opens outwardly of the upper end 14 of said block. A branch passage 19 has an upper part 20 extending downwardly at an incline from the passage 18, an intermediate passage 21 extending vertically downward from the lower end of the portion 20, andan enlarged portion 22 forming an extension of the portion 21 and which opens into the enlargement 16. T he portion 22 is preferably of frusto-conical shape to provide a valve seat. The passage 18 is provided with an angular enlargement 23 which is disposed opposite to the upper end of the passage portion 20. A second branch passage 24 is disposed on the opposite side of the vertical passage 18 from the branch passage 19 and includes an upper portion 25 which communicates with and is inclined downwardly from the passage 18, an intermediate portion 26 which extends downwardly from the lower end of the passage portion 25, and a flared lower portion 27 which opens into the passage enlargement 17 and which corresponds to the portion 22 and provides a second valve seat. The passage 18 is provided with a second enlargement 28 which is disposed opposite the upper end of the passage portion 25 and which corresponds to the enlargement 23.

The reservoir 9 contains mercury, as indicated at 29, which fills said reservoir and the lower part of the passage 15 up to the level as indicated in FIGURE 1 when no pressure exists in the passage 13 and the reservoir chamer 11 above the mercury. A valve 30 of frusto-conical shape is contained in the enlargement 16 and the valve seat 22 and is supported in an open position by the mercury in the passage 15 when the passage 13 is not pressurized. Under the same conditions, a valve 31, cor responding to the valve 30, is similarly disposed in the enlargement 17 and valve seat 27. The valves 30 and 31 are each formed of an electrical conducting material.

A sleeve 32 of electrical conducting material is secured in the passage portion 21, and a sleeve 33 of electrical conducting material is secured in the lower end of the passage portion 26. An electrical conductor 34 is connected to and leads from the sleeve 32 and an electrical conductor 35 is connected to and leads from the sleeve 33. The conductors 34 and 35 both connect with one side, preferably the negative side, of a conventional source of electrical current, designated generally 36.

For the purpose of illustrating one application and use of the automatic pump control or switch 7, a sewer pit 37 is illustrated in FIGURE 2 having an inlet 38 and an overflow 39. The overflow outlet 39 is disposed above the level of the inlet 38. An electric pump 40 has an inlet conduit 41 communicating therewith and provided with an inlet end 42 which opens into the sewer pit 37 near the bottom 43 thereof. Said pump 40 has an outlet conduit 44 leading therefrom. A second electric pump 45 has an inlet conduit 46 which communicates .therewith and has inlet end 47 which is disposed in the sewer pit near its bottom 43, and an outlet conduit 48 which leads from the outlet side of said .pump 45' A tube or pipe 49 has one end portion extending down into sewer pit 37, the open end 50 of which opens into said sewer pit near its bottom 43. The other end 51 of the conduit 49 is secured and sealed in the upper end of the passage 13. A broken line 52 represents a low liquid level in the sewer pit 37 and a broken line 53 represents a high liquid level in said sewer pit. It will be noted that the conduit ends 42, 47 and 50 are located below the low liquid level line 52 and that the sewer inlet 38 and outlet 39 are disposed above the high liquid level line 53.

The tube 49 is filled with air except for the liquid in the end portion thereof which is disposed in the sewer pit 37 and which is adjacent the liquid level in said sewer pit. When the liquid level in the sewer pit 37 is at approximately the level as indicated by the line 52, substantially no pressure will exist in the conduit 49 or the passage 13 and the mercury 29 will be disposed at the level as indicated in FIGURE 1 with the valves 30 and 31 supported in open positions thereon. A conductor 54 leads from the other side of the current source 36 to a contact 57 which is disposed in the reservoir chamber 12 and in electrical contact with the mercury 29. An electric motor 55 of the pump 40 is interposed in the conductor 34 and an electric motor 56 of the pump 45 is interposed in the conductor 35. When the mercury level is as shown in FIGURE 1, the circuits of both of the motors 5'5 and 56 are in open positions so that neither the pump 40 nor the pump 45 will be in operation, due to the lower liquid level 52 in the sewer pit 37.

As the liquid level rises in the sewer pit 37 toward the level 53, the rising liquid will pressurize the air in the pipe 49, passage 13, and in the upper part of the reservoir chamber 11, above the mercury 29 contained therein, for forcing the mercury downwardly in the reservoir chamber 11, under the partition and into the smaller reservoir chamber 12. This will cause the mercury to rise in the reservoir chamber 12 and passage 15. As the passage 15 is filled, the valve-s 30 and 3-1 will rise and will close and seal the valve seats 22 and 27 as the mercury level approaches the top of the reservoir chamber 12 and passage 15, so that none of the mercury can rise into valve seats 22 and 27. Thereafter, the mercury 29 will rise in the vertical passage 18 until it reaches approximately the level as seen in FIGURE 3 with a part of the mercury filling the lower part of the recess 23. At approximately this position, the top surface of the mercury between the recess 23 and the bottom edge of the upper end of the passage portion will assume a convex shape as indicated by the broken line 58, due to surface tension of the mercury. Immediately thereafter when the mercury column has risen slightly higher in the passage 18, the surface tension will be broken so that a quantity of the mercury, as indicated by the broken arrow tipped line 59, will flow down the branch passage 19 and will come to rest on a valve 30 so that the upper part of the valve seat 22 and the lower part of the conductor sleeve 32 will be submerged in the mercury. This will occur as the liquid level reaches the line 53 in the sewer pit 37, and will complete an electric circuit from the current source 36 through the conductor 34, in which the pump motor 55 is interposed, to the contact 32, through the mercury 29 to and through the conductor 30, through the mercury 29 beneath said conductor 30 to the conductor 57, and the conductor wire 54 back to the other side of the current source 36, for operating the pump 40 for extracting liquid from the sewer pit 37 through the conduits '41 and 44.

This will normally cause the liquid level in the sewer pit 37 to recede. By the time that the liquid level has fallen below the line 52, the mercury 29 will have drained from the passage 18, and will have lowered sufficiently in the passage 15 to permit the valve 30 to become unseated. When this occurs, the small mass of mercury supported thereon, as seen in FIGURE 3, will be released to descend into the passage enlargement 16 between the valve 30 and the valve seat 22. As this mercury moves out of engagement with the conductor 32 the aforementioned electric circuit will be interrupted to deenergize the motor 55 and stop operation of the pump 40. It will thus be seen that this starting and stopping of the pump 40 will be accomplished automatically by the pump control 7 which is located remote from the sewer pit 37.

Should the operation of the pump 40 be insufficient to effect lowering the liquid level in the sewer pit 37 and the liquid level therein continues to rise while the pump 40 is operating, the mercury column would then continue to rise in the passage 18 until it appeared as seen in FIG- URE 4. The top of the mercury column will assume a convex shape, as indicated by the broken line 60 of FIGURE 4, between the recess 28 and the bottom edge of the upper end of the passage 24, immediately before the surface tension of the mercury is broken to allow a quantity of the mercury to flow down the passage 24, as indicated by the broken arrow-tipped line 61, to come to rest on the closed valve 31 for filling the upper end of the valve seat 27 and the lower part of the conductor 33. This will complete the other electric circuit including the conductor 35 containing the pump motor 56, the conductor sleeve 33, the conductor valve 31 between the mercury 29 disposed above and beneath said valve to the contact 57 and conductor wire 54 and back to the current source, to thus complete an electric circuit for operating the other pump 45. After the liquid level has been lowered by the operation of the two pumps to the line 52 of FIG- URE 2, the two valves 30 and 31 will open simultaneously to release the mercury supported thereby for thereby interrupting the operation of the tWo pumps. A tube or pipe 62 has a lower end connected to the upper end of the passage 18 and has an upwardly opening upper end, not shown. Said tube 62 isprovided to prevent a loss of mercury should the mercury rise to above the upper end of the passage 18 before the two pumps can commence to lower the liquid level in the sewer pit 37.

The block 8 may be made of clear plastic so that the level of the mercury 29 therein will visually indicate the approximate liquid level in the sewer pit 37. The block 8 may be formed of two recessed halves which may be heat welded together after assembly of the parts 30, 31, 32, 33, 34, 35, 54 and 57 therein.

The automatic pump control 7 could be enlarged and provided with additional branch passages and additional valves if utilized to automatically control a greater number of pumps. Also, it is apparent that the control 7 may be utilized for controlling the liquid level in other types of containers, for example, containers where a pump or pumps are utilized for filling rather than emptying the containers.

Various other modifications and changes are contemplated and may obviously be resorted to, without departing from the function or scope of the invention, as hereinafter defined by the appended claims.

I claim as my invention:

1. An automatic pump control comprising a block of electrical insulating material, said block being recessed to provide a reservoir, a horizontal passage, a vertical passage and a branch passage, said reservoir having a large chamber and a small chamber, a passageway connecting said chambers adjacent the bottom of the reservoir,

a liquid of electrical conducting material contained in thereservoir, said horizontal passage communicating with the upper part of the small reservoir chamber and the lower end of said vertical passage, said branch passage connecting with the vertical passage above the horizontal passage and having a flared lower end forming a valve seat opening into the horizontal passage and spaced from said vertical passage and the reservoir, a buoyant valve of electrical conducting material for closing said valve seat, pressure responsive means adapted to connect the top of said large reservoir chamber to a receptacle containing liquid whereby a change in the liquid level in the receptacle will effect a change in the pressure in the top of the large reservoir chamber so that as the pressure increases in the top of the large reservoir chamber the liquid contained therein will be forced through the small reservoir chamber into the horizontal passage for lifting the buoyant valve to close the valve seat and will thereafter rise in said vertical passage and overflow into the branch passage therefrom, an electrical conductor submerged in the liquid of the reservoir below said valve, an electrical conductor submerged in the liquid above said valve and spaced from the valve, and an electric circuit including said conductors and adapted to include an electric motor of a pump of the receptacle whereby said circuit will be closed when the liquid in the vertical passage overflows into the branch passage to operate the pump to effect a change in the liquid level in the receptacle and to reduce the pressure in the top of the large reservoir chamber.

2. An automatic pump control as in claim 1, a second branch passage formed in said block having an upper end communicating with the vertical passage above the first mentioned branch passage and having a lower end defining a second valve seat opening downwardly into the horizontal passage, a second buoyant valve of electrical conducting material for closing said second valve seat when the horizontal passage is filled with the reservoir liquid, a third electrical conductor disposed in said second branch passage, spaced from said second valve and submerged in the liquid overflowing into the second branch passage from the vertical passage, and said electric circuit being adapted to include a second electric pump motor interposed in said third conductor for completing a circuit to the second pump of the receptacle when the reservoir liquid overflows into said second branch passage.

3. An automatic pump control as in claim 1, the liquid of said reservoir comprising mercury, said vertical passage having a recess disposed opposite to the end of the branch passage which joins with said vertical passage whereby the surface of the mercury column in the vertical passage will assume a convex shape prior to overflowing into the branch passage so that the initial overflow of the mercury into the branch passage will submerge said last mentioned electrical conductor.

4. In combination with a sewer pit including an inlet and an electric pump for extracting sewerage liquid from the sewer pit and having an inlet end opening into the sewer pit near the bottom thereof; an automatic pump control comprising a recessed block of electrical insulating material having a reservoir, a horizontal passage, a verti. cal passage and a branch passage, said reservoir having a large chamber and a small chamber, a passageway connecting bottom portions of said chambers, said horizontal passage communicating with and extending from the upper end of said chamber, said vertical passage opening downwardly into the horizontal passage, said branch passage having an upper end opening into the vertical passage and extending downwardly therefrom and a lower end opening downwardly into the horizontal passage and spaced from the reservoir and vertical passage, said lower end of the branch passage being flared to form a valve seat, a buoyant valve of electrical conducting material movably disposed in the recess of the block for closing the valve seat, a liquid of conducting material contained in said reservoir, pressure responsive means connecting the lower portion of the sewer pit to the top of the large reservoir chamber whereby an increase in the liquid contents of the sewer pit will create a pressure in the top of the reservoir chamber for forcing the liquid from the reservoir into the horizontal passage for raising the valve into a position for closing the valve seat and for thereafter forcing the liquid up the vertical passage to overflow into said branch passage, and an electric circuit including a current source having a conductor leading from one side thereof communicating with the reservoir liquid beneath said valve and a conductor leading from the other side thereof and submerged in the reservoir liquid held in said branch passage by the valve, said last mentioned conductor being spaced from said valve, said pump being interposed in the circuit wher by the pump will be operated when the large reservoir chamber is pressurized sufficiently to effect closing of the valve and discharge of the reservoir liquid into the branch passage and will be maintained in operation as long as the pressure in the large reservoir chamber is sufiicient to maintain said valve in its closed position.

5. In combination with a sewer pit including an inlet and an electric pump for extracting sewerage liquid from the sewer pit and having an inlet end opening into the sewer pit near the bottom thereof; an automatic pump control comprising a block of electrical insulating material, said block being recessed to provide a first passage, a second passage and a third passage, said second passage communicating with and extending upwardly from the first passage, said third passage having an upper end communicating with the second passage and a lower end defining a downwardly opening valve seat opening into the first passage, a buoyant valve of electrical conducting material disposed in the valve seat and in the first passage, a liquid of electrical conducting material contained in the recess of the block, pressure responsive means communi eating with the bottom portion of the sewer pit and with an upper part of the recess of the block for pressun'zing a part of the recess of the block when the liquid level rises in the sewer pit to cause the liquid vin the block to initially rise in said first passage for closing said valve and thereafter to rise in said second passage and overflow therefrom into the third passage, and an electric circuit including the motor of said pump, an electrical conductor leading from an electric current source and in electrical contact with the liquid of the block below said valve, a second electrical conductor leading from the other side of the current source and communicating with the liquid contained in said third passage and disposed above and spaced from said valve for completing an electric circuit to the pump motor when the liquid of the block overflows into the third passage and for maintaining the electric circuit closed until the liquid level falls sufficiently in the first passage to permit said valve to resume an open position.

References Cited by the Examiner UNITED STATES PATENTS 1,511,432 10/ 1924 Skidmore 103--25 2,249,994 7/ 1941 Warrick 10325 2,608,609 8/1952 Fitch 10325 3,136,871 6/ 1964 Barletta 200-81 LAURENCE V. EFNER, Primary Examiner. 

1. AN AUTOMATIC PUMP CONTROL COMPRISING A BLOCK OF ELECTRICAL INSULATING MATERIAL, SAID BLOCK BEING RECESSED TO PROVIDE A RESEVOIR, A HORIZONTAL PASSAGE, A VERTICAL PASSAGE AND A BRANCH PASSAGE, SAID RESERVOIR HAVING A LARGE CHAMBER AND A SMALL CHAMBER, A PASSAGEWAY CONNECTING SAID CHAMBERS ADJACENT THE BOTTOM OF THE RESERVOIR, A LIQUID OF ELECTRICAL CONDUCTING MATERIAL CONTAINED IN THE RESERVOIR, SAID HORIZONTAL PASSAGE COMMUNICATING WITH THE UPPER PART OF THE SMALL RESERVOIR CHAMBER AND THE LOWER END OF SAID VERTICAL PASSAGE, SAID BRANCH PASSAGE CONNECTING WITH THE VERTICAL PASSAGE ABOVE THE HORIZONTAL PASSAGE AND HAVING A FLARED LOWER END FORMING A VALVE SEAT OPENING INTO THE HORIZONTAL PASSAGE AND SPACED FROM SAID VERTICAL PASSAGE AND THE RESERVOIR, A BUOYANT VALVE OF ELECTRICAL CONDUCTING MATERIAL FOR CLOSING SAID VALVE SEAT, PRESSURE RESPONSIVE MEANS ADAPTED TO CONNECT THE TOP OF SAID LARGE RESERVOIR CHAMBER TO A RECEPTACLE CONTAINING LIQUID WHEREBY A CHANGE IN THE LIQUID LEVEL IN THE RECEPTACLE WILL EFFECT A CHANGE IN THE PRESSURE IN THE TOP OF THE LARGE RESERVOIR CHAMBER SO THAT AS THE PRESSURE INCREASES IN THE TOP OF THE LARGE RESERVOIR CHAMBER THE LIQUID CONTAINED THEREIN WILL BE FORCED THROUGH THE SMALL RESERVOIR CHAMBER INTO THE HORIZONTAL PASSAGE FOR LIFTING THE BUOYANT VALVE TO CLOSE THE VALVE SEAT AND WILL THEREAFTER RISE IN SAID VERTICAL PASSAGE AND OVERFLOW INTO THE BRANCH PASSAGE THEREFROM, AN ELECTRICAL CONDUCTOR SUBMERGED IN THE LIQUID OF THE RESERVIOR BELOW SAID VALVE, AN ELECTRICAL CONDUCTOR SUBMERGED IN THE LIQUID ABOVE SAID VALVE AND SPACED FROM THE VALVE, AND AN ELECTRIC CIRCUIT INCLUDING SAID CONDUCTORS AND ADAPTED TO INCLUDE AN ELECTRIC MOTOR OF A PUMP OF THE RECEPTACLE WHEREBY SAID CIRCUIT WILL BE CLOSED WHEN THE LIQUID IN THE VERTICAL PASSAGE OVERFLOWS INTO THE BRANCH PASSAGE TO OPERATE THE PUMP TO EFFECT A CHANGE IN THE LIQUID LEVEL IN THE RECEPTACLE AND TO REDUCE THE PRESSURE IN THE TOP OF THE LARGE RESERVOIR CHAMBER. 